The fiancee of a Saudi journalist who disappeared after entering the country's consulate in Istanbul last week said he had been 'somewhat concerned that he could be in danger,' but that he did not fear anything would happen to him at the diplomatic outpost.

Hatice Cengiz wrote in the Washington Post that her fiance, Jamal Khashoggi, first went to the consulate on September 28 and returned last week for an appointment to pick up paperwork the couple needed to get married. He has not been seen since.

Cengiz expressed confidence in the ability of Turkish authorities to figure our what happened to Khashoggi, and further called on U.S. President Donald Trump to 'help shed light' on the journalist's disappearance. She also urged Saudi Arabia's leaders to release security camera video from the consulate area.

Saudi Arabia has said Khashoggi left the consulate and rejected accusations from Turkish officials who said he was murdered there. Neither side has shown any proof to support its version of what happened.

This image taken from CCTV video obtained by the Turkish newspaper Hurriyet and made available on Oct. 9, 2018 claims to show Saudi journalist Jamal Khashoggi entering the Saudi consulate in Istanbul, Oct. 2, 2018.

Khashoggi has been critical of the Salman government, including in a number of Washington Post columns about Crown Prince Mohammed bin Salman, and has been living for a year in self-imposed exile in the United States after a Riyadh crackdown on dissent in the kingdom.

'Silence, denials and delays are not acceptable. We demand to know the truth,' Ryan said in a statement.

The pro-government Turkish newspaper Sabah said Wednesday it identified a group of 15 Saudis who allegedly traveled to Istanbul the day Khashoggi went missing, then left Turkey later that day.

Turkish police have been looking into two private aircraft that were believed to be carrying the group when they landed at the Istanbul airport on October 2. Sabah reported that both planes returned to Riyadh, with one stopping first in Dubai and the other in Egypt. The planes belonged to a Saudi company with links to the government.

Turkey's Foreign Ministry said Tuesday authorities would search the Saudi consulate, but there have been no details about when such a search would take place.

WATCH: US response to Khashoggi's case

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U.S. President Donald Trump told reporters at the White House he plans to talk to the Saudis about the case, but had no information about Khashoggi's fate.

Turkish President Recep Tayyip Erdogan said Saudi officials need to prove that Khashoggi left the building.

'We have to get an outcome from this investigation as soon as possible. The consulate officials cannot save themselves by simply saying, 'He has left,'' Erdogan said Monday on a visit to Budapest.

Saudi Crown Prince Mohammed bin Salman said last week that Riyadh was 'ready to welcome the Turkish government to go and search our premises,' because it had 'nothing to hide' about the missing journalist.